:root {
  --ink: #1a1a1a;
  --ink-soft: #5c5c5c;
  --paper: #fdfcfa;
  --rule: #ddd9d2;
  --link: #1a1a1a;
}

@media (prefers-color-scheme: dark) {
  :root {
    --ink: #e8e6e3;
    --ink-soft: #9c9892;
    --paper: #16161a;
    --rule: #34343a;
    --link: #e8e6e3;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  padding: 0 1.25rem;
  background: var(--paper);
  color: var(--ink);
  font-family: Charter, Georgia, "Times New Roman", serif;
  font-size: 21px;
  line-height: 1.6;
  -webkit-text-size-adjust: 100%;
}

a { color: var(--link); text-underline-offset: 0.15em; }
a:hover { text-decoration-thickness: 2px; }

/* --- Header --- */

.site-header {
  max-width: 40rem;
  margin: 0 auto;
  padding: 2rem 0 1.25rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.5rem;
  align-items: baseline;
  justify-content: space-between;
  border-bottom: 1px solid var(--rule);
}

.site-title {
  font-weight: 600;
  letter-spacing: 0.02em;
  text-decoration: none;
}

.site-nav {
  display: flex;
  gap: 1.1rem;
  font-size: 0.925rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.site-nav a { color: var(--ink-soft); text-decoration: none; }
.site-nav a:hover { color: var(--ink); text-decoration: underline; }
.site-nav a[aria-current="page"] { color: var(--ink); }

/* --- Page --- */

.page {
  max-width: 40rem;
  margin: 0 auto;
  padding: 2.5rem 0 3rem;
}

.page-title {
  font-size: 2.05rem;
  line-height: 1.2;
  font-weight: 600;
  margin: 0 0 2rem;
}

.page-body h2 {
  font-size: 1.375rem;
  line-height: 1.3;
  margin: 2.5rem 0 0.6rem;
}

.page-body h3 {
  font-size: 1.175rem;
  margin: 2rem 0 0.5rem;
}

.page-body p { margin: 0 0 1.1rem; }

.page-body ul { padding-left: 1.2rem; }
.page-body li { margin-bottom: 0.6rem; }

.page-body hr {
  margin: 2.5rem 0;
  border: 0;
  border-top: 1px solid var(--rule);
}

.page-body blockquote {
  margin: 0 0 1.1rem;
  padding-left: 1rem;
  border-left: 2px solid var(--rule);
  color: var(--ink-soft);
}

.page-body code {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.85em;
}

.page-body img { max-width: 100%; height: auto; }

/* --- Workings link --- */

.workings-link {
  margin-top: 3rem;
  padding-top: 1rem;
  border-top: 1px solid var(--rule);
  font-size: 0.975rem;
  color: var(--ink-soft);
}

.workings-link a { color: var(--ink-soft); }

/* --- Workings back-link --- */

.workings-back {
  margin: 0 0 1.5rem;
  font-size: 0.975rem;
  color: var(--ink-soft);
}

.workings-back a { color: var(--ink-soft); }

/* --- 404 --- */

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  margin: -1px;
  padding: 0;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}

.notfound {
  margin: 0 0 2rem;
}

.notfound img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 34rem;
  margin: 0 auto;
}

.notfound-links {
  text-align: center;
  color: var(--ink-soft);
}

/* --- FAQ contents --- */

.toc {
  margin: 0 0 3rem;
  padding: 0.9rem 1.5rem;
  border: 1px solid var(--rule);
}

.toc summary {
  cursor: pointer;
  font-size: 0.975rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

.toc summary:hover { color: var(--ink); }

.toc details[open] summary {
  margin-bottom: 0.75rem;
}

.toc ul {
  margin: 0;
  padding: 0;
  list-style: none;
}

.toc li {
  margin: 0 0 0.35rem;
  line-height: 1.35;
}

.toc a {
  color: var(--ink);
  text-decoration: none;
}

.toc a:hover { text-decoration: underline; }

/* --- Anchor links on headings --- */

.heading-anchor {
  margin-left: 0.4em;
  color: var(--ink-soft);
  text-decoration: none;
  font-weight: 400;
  opacity: 0;
  transition: opacity 0.12s;
}

h2:hover > .heading-anchor,
h3:hover > .heading-anchor,
.heading-anchor:focus {
  opacity: 1;
}

@media (hover: none) {
  .heading-anchor { opacity: 0.4; }
}

:target {
  scroll-margin-top: 1.5rem;
}